This invention relates to a brake pedal assembly for providing a master cylinder with an operational input to effect a brake application.
In brake systems of most motor vehicles, a certain amount of lost motion occurs in moving the brake shoes or brake pad into engagement with the brake drum or rotors. The brake pedal movement required to bring the brake systems into operation can account for as much as one third of the total operational stroke of a brake pedal. If the height of the brake pedal with respect to the floor of a vehicle is increased to compensate for additional pedal movement, an operator is required to raise his foot to a different height than the accelerator to move the brake pedal rather than merely rotating the foot from the accelerator to the brake pedal as now experienced by most drivers in currently produced vehicles.
Several attempts have been made to develop brake pedal linkages which change the ratio movement of an output push rod as compared to the brake pedal such as the toggle linkage disclosed in U.S. Pat. No. 3,142,199, the lever and diaphragm arrangement disclosed in U.S. Pat. No. 3,263,428, the slotted lever disclosed in U.S. Pat. No. 3,063,427, the resiliently positioned levers in U.S. Pat. No. 3,633,366 and the lever and cam arrangement disclosed in U.S. Pat. No. 3,646,831. The disadvantage in many of these prior art brake pedals is the numerous parts required to cofunction to produce a variance in the movement of the output push rod as compared to the input movement of a brake pedal.
In copending U.S. patent application Ser. No. 830,923 a brake pedal arrangement having a lever positioned by a cam is disclosed for providing a push rod with varying movement to rapidly bring the components in a brake system to an operational condition without an increase in the currently available brake pedal travel while allowing the brake pedal and accelerator to remain in substantially the same plane with respect to the foot of the operator.